Icon classes (like jp-icon0) do not work in launcher tabs for kernels

[krassowski]

Description

@krassowski Your SVG does not work for me.

The jp-LauncherCard-icon is embedded as img and seems to prevent jp-icon0 from working.

Originally posted by @benz0li in betatim/vscode-binder#61 (comment)

Reproduce

jupyterlab/packages/launcher/src/widget.tsx

Lines 299 to 306 in f14c891

	<div className="jp-LauncherCard-icon">
	{kernel ? (
	item.kernelIconUrl ? (
	<img
	src={item.kernelIconUrl}
	className="jp-Launcher-kernelIcon"
	alt={title}
	/>

Expected behavior

We should allow for theme-responsive icons in launcher

We could:

• embed SVG directly (needs sanitization!)
• explore Support for passing CSS styles to an SVG used via img[src] w3c/csswg-drafts#8634 or CSS linked parameters approach

Context

• JupyterLab version: 4.2.0

[krassowski]

Another solution would be having two different sets of icon URLs, one for dark theme and one for light theme.

[krassowski]

After researching a few solutions, it looks like the best short-term solution is indeed setting the preferred-color like this:

<div style="color-scheme: dark">
  <img />
</div>

based on the current JupyterLab theme.